Electro-optical lock and method

ABSTRACT

A finger operated electro-optical lock system in which an optical keyboard having a plurality of zones indicated thereon is illuminated by infrared energy and where the pattern or sequence in which the finger is placed in proximity to the zones to render them reflective are evaluated to open a lock.

Emited States Patent 1191 Clark, Jr. Oct. 30, 1973 [54] ELECTRO-OPTICAL LOCK AND METHOD 3,029,345 4/1962 Douglas.., 317/134 3,587,051 6/1971 Hovey 317/134 [751 Invent 9" Llghthwse 3,536,894 10/1970 TraViOli 340/149 Point, Fla.

[73] Assignee: Polar Corporation, West Pompano Beach, PM Primary Examiner-Harold A. D1xon Att0meyL. Lawton Rogers, 111 [22] Filed: Oct. 6, 1972 21 Appl. No.: 295,483

[57] ABSTRACT [52] U.S. C1 250/341, 250/345, 250/347,

134 A finger operated electro-optical lock system in which [51] Int. Cl B62j 3/00 an optical keyboard having a plurality of zones indi- [58] Field of Search 70/278; 317/134; ared thereon is illuminated by infrared energy and 345 where the pattern or sequence in which the finger is placed in proximity to the zones to render them reflec- [56] Ref r nces C d tive are evaluated to open a lock.

UN1TED STATES PATENTS 3,567,909 3/1971 Allen 340/149 23 Claims, 5 Drawing Figures OSCILLATOR L.E.D.'s

I 1 l6 4 z y r (ML 1 W. 44 I8 1 1 r DETECTORS 20 1' w w w j 1 L 28 W X Y Z l 1 1 '1 l B C D l 1 1 30 DEMODULATOR LOCK EVALUATOR PATENTED OCT 30 4975 FIG. 2 (L).lllLlJlllL|llllUl l l lllIllLlUllHJJlIIUil- LE. D.'s

OSC I LLATOR TIME,

30 DEMODULATOR EVALUATOR LOCK mm F DCBA ELECTRO-OPTICAL LOCK AND METHOD BACKGROUND OF THE INVENTION The present invention relates to an optical keying system and more particularly to an electro-optic al system for operating a locking mechanism from a point externally of a building to which entry is desired.

Electronic combination locking systems in which a series of switches are set in a predetermined combination in order to release a locking mechanism are well known. The combination indicating devices for these systems are generally mechanically actuated switches which are subject to mechanical wear. Moreover, many of the electronic locking systems operate on the principle of selecting a predetermined combination by simultaneously positioning switches corresponding to the predetermined combination. These systems have the disadvantage that the requirement of simultaneous actuation or setting of the switches to the predetermined combination may offer an observer a view of the combination before it is possible to move the switches away from their combination indicating positions.

The use of electromagnetic and optical scanners to read a card or other key inserted into a slot is generally known and may be found, for example, in the operation of parking lot closures. All systems of this type suffer from the disadvantage that the slot into which the key must be placed may be obstructed by leaves, twigs, dirt and the like by children and by vandals. In addition, the combinations of such systems has not been readily modifiable.

It is accordingly an object of the present invention to obviate the deficiency of these known systems and to provide a novel and improved electro-optical locking system and method in which optical keys are actuated in a predetermined sequence for operating a locking mechanism.

It is another object of this invention to provide a novel system and method in which the combination of the mechanism may be easily and quickly manually modified.

It is yet another object of the invention to provide a novel circuit and method for evaluating a predetermined sequence of optical key actuations.

It is yet another object of the present invention to provide a novel system and method for operating a lock in which all of the operable parts thereof are located internally of the structure into which entry is desired.

It is still another object of the present invention to provide a novel optical keyboard actuated by the presence of the human finger at a preselected zone on the board.

These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from the claims and from the perusual of the following detailed description in connection with the appended drawings.

THE DRAWINGS FIG. 1 is a functional block diagram of the system of the present invention;

FIG. 2 is a series of graphs of the waveforms occurring at various points in the circuit of FIG. 1;

FIG. 3 is a pictorial view in elevation of the optical keyboard of the system of FIG. 1; i

FIG. 4 is a section in elevation taken through the optical keyboard of FIG. 3 with the position of the optical elements schematically illustrated; and,

FIG. 5 is a schematic circuit diagram of the evaluator of FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT With reference now to FIG. 1, a power supply such as an oscillator 10 is utilized to energize a light source such as a plurality of light emitting diodes (LEDs) 12 to continuously illuminate a plurality of zones 14-20 of a sheet 22 of radiation pervious material such as glass. The light source 12 may radiate only in the infrared portion of the electromagnetic spectrum or may radiate over a wide frequency band including the infrared spectrum for purposes which will become apparent hereinafter.

In the illustrated embodiment, the light source 12 comprises a plurality of light emitting diodes (LEDs) one each associated with a corresponding zone 14-20 of the sheet 22. The LEDs may be energized by pulses from the oscillator 10 rather than a steady state source to increase the average power and thus the radiation output therefrom. A detector array 24 may be located on the same side as the sheet 22 as the LEDs 12 and, as hereinafter described in connection with FIG. 4, each detector in the array may be shielded from direct radiation from the LEDs. In addition, each detector may be shielded from reflected radiation except that radiation coming from the direction of a predetermined one of the zones 14-20. The positioning of a radiation returning object 26 in proximity to one of the zones 14-20 may thus be detected only by the one of the detectors 24 associated with that zone.

The return of radiation may be achieved by reflection of the radiation from the LEDs 12 by an object 26 placed in proximity to the other side of the sheet 22 back through the sheet 22 towards the associated one of the detectors 24. Alternatively, the object 26 may absorb energy directed towards a zone and then reradiate energy from the zone to the corresponding one of the detectors 24. The detectors 24 may also be actuated by direct radiation from a radiating object held in proximity to the zones 1.420. An exposed portion of the human body such as the human finger has been found quite satisfactory as have many light colored objects where the radiation is in the infrared band.

The output signals from the individual one of the detectors 24 are applied to a combination selector 28 having a plurality of input terminals W, X, Y and Z each manually selectively connected to one of a plurality of output terminals A, B, C and D. The sequence in which the connections are established determines the code or combination of the lock. In the example illustrated, the W input terminal is connected to the C output terminal, the X input terminal is connected to the A output terminal, the Y input terminal is connected to the B output terminal and the Z input terminal is connected to the D output terminal. The output terminals A, B, C and D of the combination selector 28 are connected to corresponding input terminals A, B, C and D of a demodulator 30 and the output signals from the demodulator 30 are applied to an evaluator 32 which controls the operation of a lock 34.

In operation, the oscillator 10 pulses the LEDs 12 to illuminate all of the zones 14-20 of the optical keyboard 22. The positioning of a human finger or other radiation returning object 26 in proximity to one of the zones 14-20 of the keyboard 22 returns radiation to the one of the detectors 24 associated with that particular zone. The selective sequential positioning of the object 26 in proximity to each of the zones 14-20 thus results in the application of pulses successively to the combination selector 28.

The manual positioning of the switch elements of the combination selector 28 serves to alter the order in which the pulses from the detectors 24 are applied through the demodulator 30 to the evaluator circuit 32. The order in which the object 26 is positioned in proximityto the zones 14-20 thus must complement the selected combination for the pulses from the combination selector 28 to appear in the order for which the evaluator circuit 32 is preset. In the illustrated example, radiation must be detected by the detection associated with the zones 16, 18, 14 and 20 in that order to provide successive pulses on the input terminals A, B, C and D of the evaluator circuit 32. As will be hereinafter explained in greater detail, the detection of a single out-of-order pulse will reset the evaluator circuit 32 requiring that the entire sequence be correctly repeated.

With continued reference to FIG. 1 and with reference to the waveforms of FIG. 2, the oscillator may provide the LEDs 12 with a series of impulses having, by way of example, a pulse repetition rate of 200 KHZ. The LEDs may, upon the application of each of the impulses, radiate electromagnetically in a wide band including energy in the infrared portion of the electromagnetic spectrum. The LEDs 12 may be operated in a continuous pulse mode as illustrated by the waveform (L) of FIG. 2. The return of radiation from the zone 16 will be detected by the associated one of the detectors 24 for the interval of time tl-tz to provide an output signal illustrated by the waveform (M) of FIG. 2. The signal of FIG. 2(M) is applied from the terminal. X to the terminal A by the combination selector 28 to the terminal A of the demodulator 30 .The demodulator 30 produces a pulse envelope such as illustrated by the waveform (N) of FIG. 2 for application to the evaluator circuit 32.

The physical relationship of the keyboard may be as illustrated in FIGS. 3 and 4. With reference now to FIGS. 3 and 4, an opening 36 may be provided from the inside of an external wall and the opening covered by a one-quarter inch thick sheet 38 of plate glass or other radiant energy transparent material having the desired structural characteristics. Any suitable conventional means such as a metallic plate 40 and a plurality of threaded fasteners 42 may be utilized to mount the sheet 38 over the opening 36. Thus, a convenient window is provided against which the radiant energy returning object 26 of FIG. 1 may be positioned.

As indicated in FIGS. 1 and 3, a plurality of potentially reflective zones 14-20 may be provided in the window by the positioning of the diodes 12. As indicated schematically in FIG. 4, each one of the light emitting diodes 12 has associated therewith one of the detectors 24. Suitable shields or baffles may be procouple the radiant energy from that one of the diodes 12 to the associated one of the detectors 24. Likewise, the absence of a radiation reflective object at the zone against which radiant energy from the one of the diodes 12 associated therewith will produce no output signal from the associated one of the detectors 24.

One embodiment of the evaluator circuit 32 of FIG. 1 is shown in FIG. 5. In this embodiment, four .IK flipflops F/Fl-F/F4 are serially connected such that the true and false output terminals Q and 6 each of a flipflip are connected to the .I and K input terminals respectively of the succeeding flip-flop. The true and false output terminals Q and 6 of the last flip-flop F /F4 are connected respectively to the .I and K input terminals of the first flip-flop F/Fl.

The Q and 6 output terminals of each of the flipflops F /FlF/F4 are connected to one input terminal of one of eight two input terminal NAND gates NI-NS. As illustrated, the other input terminal of each of the NAND gates N1 and N2 is connected to the output terminal A of the demodulator 30. Similarly, the output terminal B of the demodulator is connected to the other input terminals of the NAND gatesN3 and N4. In a like manner, the gates N5 and N6 each have one input terminal thereof connected to the C output terminal of the demodulator 30 and the other input terminal of the NAND gates N7 and N8 is connected to the D output terminal of the demodulator 30.

The output terminals of the NAND gates N1, N3, N5 and N7 associated with the false output terminals 6 of the flip-flops F/Fl-F/F4 are connected to the reset input terminal R of a conventional bistable multivibrator or flip-flop 44. The output terminals of the NAND gates N2, N4, N6 and N8 associated with the true output terminals Q of the flip-flops F/Fl-F/F4 are connected to the set terminal S of the flip-flop 44 and through an inverter 46 to the trigger input terminals T of each of the flip-flops F/Fl-F/F4.

A suitable source of positive potential may be connected to the reset input terminal R of the flip-flop 44. The false output terminal 6 of the flip-flop 44 is connected through an inverter 48 to the preset input terminal PS of the flip-flop F/Fl and to the clear input terminals C of the flip-flops F/FZ, F/F3 and F/F4.

The true output terminal Q of the flip-flop 44 is connected to one input terminal of a three input terminal NAND gate N9 and the output signal therefrom is applied to the lock 34 of FIG. 1 to effect the operation thereof. The other two input terminals of the NAND gate N9 are connected respectively to the D output ter- 7 minal of the demodulator 30 of FIG. 1 and to the true vided to optically isolate all of the detectors 24 from 7 output terminal 0 of the flip-flop F/F4.

In operation from an initial reset condition, the first flip-flop F/F 1 is in a set condition and the remaining flip-flops are in a reset condition. In this condition and as a result of the bias voltage applied to the reset input terminal R, the flip-flop 44 is in an initial condition in which a low signal level signal is applied from the true output terminal Q thereof to the NAND gate N9 thereby insuring high signal level output signal therefrom to the lock 34 of FIG. 1. The high signal level signal from the false output terminal 6 is inverted by the inverter 48 so that the flip-flops F/Fl-F/F4 are not again cleared to the initial preset condition. Since no signals appear on the input terminals A-D, none of the NAND gates N1-N7 are enabled.

The high signal level signal from the NAND gates N1, N3, N5 and N7 is applied to the reset input terminal R of the flip-flop 44 to maintain the flip-flop in a reset condition. The high signal level signal from the NAND gates N2, N4, N6 and N8 is inverted by the inverter 44 so that no trigger or clock signals are applied to the flipflops F/Fl-F/F.

With continued reference to FIG. 5 and upon the application of an input signal from the demodulator 30 of F IG. 1 to the input terminal A, the NAND gate N2 enabled by the flip-flop F/F 1 will generate a negative going signal which is inverted by the inverter to clock the flip-flops F/Fl-F/Fi. The application of this low signal level signal to the set terminal S of the flip-flop 44 will not change the state thereof.

When the signal at the input terminal A is removed by the removal of the finger or other object from the keyboard 22 of FIG. 1, the NAND gate N2 is disabled to remove the signal from the trigger input terminals T of the flip-flops F/Fl-F/F4.

The binary states of the flip-flops F/Fl-F/F4 are given in the following Table 1 as successive signals are applied to the input terminals A, B, C and D in that order:

TABLE 1 F/ll F/F 2 F/Ifi F/Fi Q Q Q Q Q Q Q Q Reset l, O 0, l 0, l O, l After A 0,] 1,0 O,l 0,] After B 0,1 0,l l, 0,1 After C O, l 0,1 0,1 l, 0 After D 1,0 0, l O, l O, 1

As shown in Table 1, the flip-flop F/F3 provides an enabling signal to the NAND gate N9 at the time that the signal on the input terminal D appears and the NAND gate N9 operates the lock 34 of FIG. 1. Thus the NAND gates N2, N4, N6 and N8 are successively enabled by advancement of the counter and the coincidence of input pulses on the input terminals A, B, C and D acts to enable the next succeeding flip-flop F/Fl-F/F and thus enable the next pair of the NAND gates N1 and N2, N3 and N4 and N5 and N6.

The coincidence of the input signal on the input terminal D with the prior setting of the flip-flop F/F3 at a time that the flip-flop 44 is in a set condition will provide a low signal level output signal from the NAND gate N9 to the lock 34 of FIG. 1. Thus the operation of the lock 34 requires that the flip-flops F/Fl-F/F4 will be successively triggered by signals on the input terminals A, B, C, and D in that order.

Should input signals be applied to the input terminals A, B, C and D in any order other than A, B, C and D, the out-of-order pulse will enable one of the NAND gates N1, N3, N5 or N7 to provide a low signal level to the set input terminal S of the flip-flop 44. The positive bias on the reset input terminal R of the flip-flop effects a change in the state thereof and the low signal level signal from the true output terminal Q inhibits the NAND gate N9 to prevent operation of the lock 34 of FIG. 1. At the same time the high signal level signal from the false output terminal 6 of the flip-flop 44 is inverted in the inverter 48 to reset the flip-flops F/Fl-F/F.

In summary, the flip-flops F/F1-F/F4 function as a 6 a signal from the NAND gate N9 effects release of the lock 34. It will be appreciated that to release the locking mechanism, there must be at the input terminals of the NAND gate N9 asignal indicating that the shift register has not been reset, that the next to the last input signal for the sequence has been received in the proper sequence; and, that the last input signal for the sequence has been received.

ADVANTAGES AND SCOPE OF THE INVENTION Many of the advantages of the present invention will be readily apparent from the foregoing description of a preferred embodiment. For example, the optical keyboard of the present invention utilizes the infrared region of the electromagnetic spectrum to avoid false triggering due to ambient light. It will be appreciated, however, that with appropriate thresholding circuits, energy in other regions of the electromagnetic spectrum may be utilized. The infrared region of the electromagnetic spectrum is uniquely suited for optical keyboards in that the human finger adequately reflects or returns the energy to the detectors.

Another of the major advantages of the present system is that observation of the sequence in which the finger or other energy returning object is placed in proximity to the zones of the keyboard is easily hindered to protect the combination of the lock. Further, sequential activation precludes any residual indication of the combination as may exist where the combination is set by a plurality of switches or the like.

Because of the resetting of the shift register upon the detection of a single out-of-sequence pulse, security is assured. It will be further appeciated that the combination cannot be detected by a sense of feel or mechanical noise since no mechanical combination locking or unlocking apparatus is utilized.

Moreover, the ease with which the combination may be changed facilitates revision of the security measures and thus reduces the likelihood of compromise. Since the device is finger operated, there are no keys to be lost or stolen.

Another of the major advantages of the present invention is the complete lack of moving parts in the operation of the system. The use of plate glass provides the desired structural strength and obviates the necessity for an opening which may be obstructed by children or vandals.

The present invention may thus be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not as restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. An electro-optical locking system comprising:

a sheet of radiant energy pervious material;

means on one side of said sheet for directing radiant energy at said sheet;

a plurality of detectors on said one side of said sheet,

each of said plurality of detectors being positioned to respond to radiant energy returned through a predetermined zone on said sheet from a radiation returning object selectively positionable on the other side of said sheet;

a lock; and,

means responsive to said plurality of detectors for operating said lock.

2. The system of claim 1 wherein the radiant energy includes energy in the infrared frequency band.

3. The system of claim 1 wherein the radiant energy includes energy reflective by an exposed portion of the human body.

4. The system of claim 1 wherein said radiant energy directing means includes:

a plurality of light emitting diodes each having a predetermined physical relationship to one of said zones;

an oscillator for energizing said diodes; and,

means for shielding all of said plurality of detectors from direct radiant energy from all of said diodes and for shielding predetermined ones of said plurality of detectors from radiant energy reflected from said other side of said sheet.

5. The system of claim 5 wherein said lock operating means includes:

switch means for establishing a desired sequence of detector illumination; and,

counter means advanced in response to the illumination of said plurality of detectors by radiant energy in the desired sequence and reset in response to the illumination of a detector in a sequence other than the desired sequence, said lock operating means being actuated in response to an advancement of said counter corresponding to the completion of said sequence.

6. An electro-optical locking system comprising:

a sheet of radiant energy pervious material;

means on one side of said sheet for directing radiant energy at said sheet;

a plurality of detectors on said one side of said sheet, each of said plurality of detectors being positioned to respond to radiant energy returned from a predetermined zone on said sheet;

a lock; and,

means responsive to said plurality of detectors for operating said lock, said lock operating means includswitch means for establishing a desired sequence of detector illumination, and counter means advanced in response to the illumination of said plurality of detectors by radiant energy in the desired sequence and reset in response to the illumination of a detector in a sequence other than the desired sequence, said lock operating means being actuated in response to an advancement of said counter corresponding to the completion of said sequence.

7. The system of claim 6 wherein the radiant energy includes energy in the infrared frequency band; and,

wherein said radiant energy directing means includes:

a plurality of light emitting diodes each having a predetermined physical relationship to one of said zones;

an oscillator for energizing said diodes; and,

means for shielding all of said plurality of detectors from direct radiant energy from all of said diodes and for shielding predetermined ones of said plurality of detectors from radiant energy reflected from said other side of said sheet.

8. The system of claim 7 wherein the radiant energy includes energy reflective by an exposed portion of the human body.

9. The system of claim 8 wherein said sheet of material is glass having a thickness of at least about onequarter inch.

10. An optical keyboard comprising:

a sheet of transparent material;

means on one side of said sheet for directing radiation at a plurality of predetermined zones on said sheet;

a plurality of radiation responsive elements on said one side of said sheet, each of said elements being associated with at least one of said zones;

means for shielding all of said plurality of elements from direct radiation from all of said radiation directing means and for shielding all of said elements from radiation returned from all but a predetermined one or more of said zones; and,

switch means on said one side of said sheet operable in response to the radiation of said elements from an exposed finger of the human hand when placed in proximity to one of said zones on the other side of said sheet to reflect radiation from said radiation directing means to thereby illuminate one of said elements.

11. The optical keyboard of claim 10 wherein said radiation includes radiation in the infrared region of the electromagnetic spectrum.

12. The optical keyboard of claim 11 wherein said sheet is made of glass having a thickness of at least about one-quarter inch.

13. A method for operating a locking device after the completion of a predetermined sequence, comprising the steps of:

a. illuminating a number of predetermined zones with radiant energy;

b. returning radiant energy from said zones in a selected sequence;

0. detecting the reflection of radiant energy from the zones;

d. evaluating the sequence of reflection against a predetermined sequence; and,

e. generating a lock operating signal responsive to the evaluation.

14. The method of claim 13 wherein the radiant energy includes energy in the infrared region of the electromagnetic spectrum.

15. The method of claim 14 wherein the selective return of radiant energy from the zones is responsive to the placing of an infrared returning object in proximity to the zones.

16. The method of claim 15 wherein the infrared returning object is an exposed portion of the human body.

17. A method for operating a device after the completion of a predetermined sequence comprising the steps of:

a. directing radiation at a plurality of zones;

b. sequentially positioning radiation returning means in proximity to selected ones of the zones;

c. detecting the return of radiation from the zones;

and,

d. evaluating the sequence of the detection of radiation against a predetermined sequence to operate the device.

18. The method of claim 17 wherein the step of evaluating the return of radiation includes the steps of:

generating a signal unique for the detection of radiation from each zone;

evaluating each signal individually;

advancing a counter in response to a faborable evaluation and resetting the counter in response to an unfavorable evaluation upon the generation of an indicating device; and,

operating advancement of the counter through a predetermined number of advancements without reset.

19. The method of claim 18 wherein said radiation includes radiation in the infrared region of the electromagnetic spectrum; and,

wherein said radiation is returned in response to the positioning of a finger in proximity to one of the zones.

20. A system for operating the lock of an enclosure entrance comprising:

a sheet of material transparent to electromagnetic radiation in the infrared frequency band, said sheet being carried by the enclosureand providing structural integrity for the enclosure;

means on the side of said sheet internal of the enclosure for directing radiation in the infrared frequency band through a plurality of predetermined zones on said sheet;

a plurality of radiation responsive elements on the side of said sheet internal of the enclosure, each of said elements being associated with at least one of said zones;

means for shielding all of said plurality of elements from direct radiation from all of said radiation directing means and for shielding all of said elements from radiation passing through all but a predetermined one or more of said zones into the enclosure; and,

switch means on the side of said sheet internal of the enclosure operable in response to the radiation of said elements by radiation in the infrared frequency band originating internally of the enclosure and reflected from an object external of the enclosure back through said sheet to operate said switch means and thereby unlock the entrance to the enclosure.

21. The system of claim 20 wherein the object external of the enclosure from which the radiation is reflected back through said sheet is the finger of a human hand whereby the need for carrying a reflective object is obviated.

22. A method for operating the locking device of the entrance to an enclosure without comprising the integrity of the enclosure comprising the steps of:

a. passing radiant energy from a source internal of the enclosure through a number of predetermined zones of a sheet of structural material optically transparent to the radiant energy;

b. sequentially reflecting a portion of the radiant energy passed through the sheet of structural material back through the sheet into the enclosure from an object external of the enclosure;

c. identifying the zones from which radiant energy is reflected back into the enclosure;

(1. evaluating the sequence of reflection with respect to a predetermined sequence; and,

e. operating the locking device responsively to the evaluation of the reflected energy.

23. The method of claim 22 wherein the radiant energy includes energy in the infrared region of the electromagnetic spectrum and wherein the selective reflection of radiant energy through the sheet is responsive to the placing of an exposed portion of the human body in proximity to selected zones of the sheet externally of the enclosure. 

1. An electro-optical locking system comprising: a sheet of radiant energy pervious material; means on one side of said sheet for directing radiant energy at said sheet; a plurality of detectors on said one side of said sheet, each of said plurality of detectors being positioned to respond to radiant energy returned through a predetermined zone on said sheet from a radiation returning object selectively positionable on the other side of said sheet; a lock; and, means responsive to said plurality of detectors for operating said lock.
 2. The system of claim 1 wherein the radiant energy includes energy in the infrared frequency band.
 3. The system of claim 1 wherein the radiant energy includes energy reflective by an exposed portion of the human body.
 4. The system of claim 1 wherein said radiant energy directing means includes: a plurality of light emitting diodes each having a predetermined physical relationship to one of said zones; an oscillator for energizing said diodes; and, means for shielding all of said plurality of detectors from direct radiant energy from all of said diodes and for shielding predetermined ones of said plurality of detectors from radiant energy reflected from said other side of said sheet.
 5. The system of claim 5 wherein said lock operating means includes: switch means for establishing a desired sequence of detector illumination; and, counter means advanced in response to the illumination of said plurality of detectors by radiant energy in the desired sequence and reset in response to the illumination of a detector in a sequence other than the desired sequence, said lock operating means being actuated in response to an advancement of said counter corresponding to the completion of said sequence.
 6. An electro-optical locking system comprising: a sheet of radiant energy pervious material; means on one side of said sheet for directing radiant energy at said sheet; a plurality of detectors on said one side of said sheet, each of said plurality of detectors being positioned to respond to radiant energy returned from a predetermined zone on said sheet; a lock; and, means responsive to said plurality of detectors for operating said lock, said lock operating means including: switch means for establishing a desired sequence of detector illumination, and counter means advanced in response to the illumination of said plurality of detectors by radiant energy in the desired sequence and reset in response to the illumination of a detector in a sequence other than the desired sequence, said lock operating means being actuated in response to an advancement of said counter corresponding to the completion of said sequence.
 7. The system of claim 6 wherein the radiant energy includes energy in the infrared frequency band; and, wherein said radiant energy directing means includes: a pluraLity of light emitting diodes each having a predetermined physical relationship to one of said zones; an oscillator for energizing said diodes; and, means for shielding all of said plurality of detectors from direct radiant energy from all of said diodes and for shielding predetermined ones of said plurality of detectors from radiant energy reflected from said other side of said sheet.
 8. The system of claim 7 wherein the radiant energy includes energy reflective by an exposed portion of the human body.
 9. The system of claim 8 wherein said sheet of material is glass having a thickness of at least about one-quarter inch.
 10. An optical keyboard comprising: a sheet of transparent material; means on one side of said sheet for directing radiation at a plurality of predetermined zones on said sheet; a plurality of radiation responsive elements on said one side of said sheet, each of said elements being associated with at least one of said zones; means for shielding all of said plurality of elements from direct radiation from all of said radiation directing means and for shielding all of said elements from radiation returned from all but a predetermined one or more of said zones; and, switch means on said one side of said sheet operable in response to the radiation of said elements from an exposed finger of the human hand when placed in proximity to one of said zones on the other side of said sheet to reflect radiation from said radiation directing means to thereby illuminate one of said elements.
 11. The optical keyboard of claim 10 wherein said radiation includes radiation in the infrared region of the electromagnetic spectrum.
 12. The optical keyboard of claim 11 wherein said sheet is made of glass having a thickness of at least about one-quarter inch.
 13. A method for operating a locking device after the completion of a predetermined sequence, comprising the steps of: a. illuminating a number of predetermined zones with radiant energy; b. returning radiant energy from said zones in a selected sequence; c. detecting the reflection of radiant energy from the zones; d. evaluating the sequence of reflection against a predetermined sequence; and, e. generating a lock operating signal responsive to the evaluation.
 14. The method of claim 13 wherein the radiant energy includes energy in the infrared region of the electromagnetic spectrum.
 15. The method of claim 14 wherein the selective return of radiant energy from the zones is responsive to the placing of an infrared returning object in proximity to the zones.
 16. The method of claim 15 wherein the infrared returning object is an exposed portion of the human body.
 17. A method for operating a device after the completion of a predetermined sequence comprising the steps of: a. directing radiation at a plurality of zones; b. sequentially positioning radiation returning means in proximity to selected ones of the zones; c. detecting the return of radiation from the zones; and, d. evaluating the sequence of the detection of radiation against a predetermined sequence to operate the device.
 18. The method of claim 17 wherein the step of evaluating the return of radiation includes the steps of: generating a signal unique for the detection of radiation from each zone; evaluating each signal individually; advancing a counter in response to a faborable evaluation and resetting the counter in response to an unfavorable evaluation upon the generation of an indicating device; and, operating advancement of the counter through a predetermined number of advancements without reset.
 19. The method of claim 18 wherein said radiation includes radiation in the infrared region of the electromagnetic spectrum; and, wherein said radiation is returned in response to the positioning of a finger in proximity to one of the zones.
 20. A system for operating the lock of an enclosure entrance comprising: a sheEt of material transparent to electromagnetic radiation in the infrared frequency band, said sheet being carried by the enclosure and providing structural integrity for the enclosure; means on the side of said sheet internal of the enclosure for directing radiation in the infrared frequency band through a plurality of predetermined zones on said sheet; a plurality of radiation responsive elements on the side of said sheet internal of the enclosure, each of said elements being associated with at least one of said zones; means for shielding all of said plurality of elements from direct radiation from all of said radiation directing means and for shielding all of said elements from radiation passing through all but a predetermined one or more of said zones into the enclosure; and, switch means on the side of said sheet internal of the enclosure operable in response to the radiation of said elements by radiation in the infrared frequency band originating internally of the enclosure and reflected from an object external of the enclosure back through said sheet to operate said switch means and thereby unlock the entrance to the enclosure.
 21. The system of claim 20 wherein the object external of the enclosure from which the radiation is reflected back through said sheet is the finger of a human hand whereby the need for carrying a reflective object is obviated.
 22. A method for operating the locking device of the entrance to an enclosure without comprising the integrity of the enclosure comprising the steps of: a. passing radiant energy from a source internal of the enclosure through a number of predetermined zones of a sheet of structural material optically transparent to the radiant energy; b. sequentially reflecting a portion of the radiant energy passed through the sheet of structural material back through the sheet into the enclosure from an object external of the enclosure; c. identifying the zones from which radiant energy is reflected back into the enclosure; d. evaluating the sequence of reflection with respect to a predetermined sequence; and, e. operating the locking device responsively to the evaluation of the reflected energy.
 23. The method of claim 22 wherein the radiant energy includes energy in the infrared region of the electromagnetic spectrum and wherein the selective reflection of radiant energy through the sheet is responsive to the placing of an exposed portion of the human body in proximity to selected zones of the sheet externally of the enclosure. 